Starpoints

Book everything back to the room! The great thing about collecting extra Starpoints is that it is so easy. No matter what you do or have, just book it back to the room. I recently had to take a helicopter flight. It was $900, so I had the hotel organize it and charge it to my room. Nice points!

Everything Counts!
I obtain my Starpoints the following ways.
1. Register for open promotions. Flyertalk is a good source of information.
2. Use my Starwood AMEX card for all purchases.
3. Take the 500 points instead of the other gifts.
4. Have conferences at Starwood properties and charge to my Starwood AMEX card.
5. Order room service.

Using the following methods, I've amassed so many Starpoints that luckily my balance never really goes down:
1. Most important -- get the Starwood AMEX card. It's one of the best AMEX cards available, and in my opinion, almost as good as the AMEX Platinum card which costs $450 per year.
2. Promos -- go to SPG.com/promo every so often and put in your Starwood number, signing up for the relevant promotions available to you at any given time.
3. Take the 500 Starpoints on arrival as a platinum amenity.
4. Actively participate in Communispace.

Everyone seems to have covered your question. I would also suggest to add yourself to the Starwood RSS for special offers, which will included double points or more.

And don't forget to take advantage of the 5th night free on most SPG awards, it's almost like earning points.